The proposed studies focus on the development of a new paradigm for targeted cancer therapy. Our approach is based on the development of small molecules that possess the functional properties of antibodies; these functions include the ability to bind antigens with high affinity and selectivity, and the ability to trigger the action of professional phagocytic and killer cells (e.g., natural killer cells, macrophages, and dendritic cells). Such materials would combine the many advantages of antibody-based therapeutics with those of traditional small-molecule-based approaches. Here we propose to develop small molecule antibody mimics (SAMs) that bind selectively to cancer cells that overexpress the prostate-specific membrane antigen (PSMA), and induce immune-mediated cytolysis through the Fc-gamma receptor type 1 (Fc?RI). Fc?RI triggers immune cells to release cytotoxic contents only upon multivalent binding to an appropriate cell-surface-immobilized ligand. PSMA is a cell surface enzyme that is overexpressed both in prostate cancer cells and in tumor neovasculature for a wide variety of cancers (including pancreatic ductal carcinoma, colon adenocarcinoma, glioblastoma multiforme, and non-small cell lung carcinoma). Preliminary data suggests that formation of complexes between the small molecule, cancer cells, and immune cells will lead to highly selective immune-mediated cancer cell destruction. The strategy proposed here is not limited any one particular disease - the therapeutic action is determined simply by which cell type is targeted by antibody mimics. As such, we believe that the proposed research is highly significant, and constitutes a critical step toward improving the lives of patients suffering with cancer and other diseases.